scholarly journals Marine sedimentary records of chemical weathering evolution in the western Himalaya since 17 Ma

Geosphere ◽  
2021 ◽  
Author(s):  
Peng Zhou ◽  
Thomas Ireland ◽  
Richard W. Murray ◽  
Peter D. Clift
Keyword(s):  
Climate Change ◽  
Chemical Weathering ◽  
Diffuse Reflectance Spectroscopy ◽  
Global Climate ◽  
Regional Climate ◽  
River Mouth ◽  
Regional Climate Change ◽  
Western Himalaya ◽  
Surface Reactivity ◽  
Sediment Geochemistry

The Indus Fan derives sediment from the western Himalaya and Karakoram. Sediment from International Ocean Discovery Program drill sites in the eastern part of the fan coupled with data from an industrial well near the river mouth allow the weathering history of the region since ca. 16 Ma to be reconstructed. Clay minerals, bulk sediment geochemistry, and magnetic susceptibility were used to constrain degrees of chemical alteration. Diffuse reflectance spectroscopy was used to measure the abundance of moisture-sensitive minerals hematite and goethite. Indus Fan sediment is more weathered than Bengal Fan material, probably reflecting slow transport, despite the drier climate, which slows chemical weathering rates. Some chemical weathering proxies, such as K/Si or kaolinite/(illite + chlorite), show no temporal evolution, but illite crystallinity and the chemical index of alteration do have statistically measurable decreases over long time periods. Using these proxies, we suggest that sediment alteration was moderate and then increased from 13 to 11 Ma, remained high until 9 Ma, and then reduced from that time until 6 Ma in the context of reduced physical erosion during a time of increasing aridity as tracked by hematite/goethite values. The poorly defined reducing trend in weathering intensity is not clearly linked to global cooling and at least partly reflects regional climate change. Since 6 Ma, weathering has been weak but variable since a final reduction in alteration state after 3.5 Ma that correlates with the onset of Northern Hemispheric glaciation. Reduced or stable chemical weathering at a time of falling sedimentation rates is not consistent with models for Cenozoic global climate change that invoke greater Himalayan weathering fluxes drawing down atmospheric CO2 but are in accord with the idea of greater surface reactivity to weathering.

scholarly journals Hindu Kush Himalayan Ecosystem as a Common Concern of Humankind: Imperative for Better Regional Jurisprudence

2017 ◽  
pp. 42-52
Author(s):  
Debasis Poddar
Keyword(s):  
Climate Change ◽  
Global Climate Change ◽  
Global Climate ◽  
Regional Climate ◽  
Critical Role ◽  
Regional Climate Change ◽  
Mountain Glaciers ◽  
Common Concern ◽  
Hindu Kush ◽  
The World

Hindu Kush Himalayan region (hereafter the HKH) - with 3500 odd kilometres stretched in eight countries- is default resource generation hub for about one-fifth population of the world. The ecosystem-growing delicate these days- seems to play a critical role for the survival of flora and fauna along with the maintenance of all its life-sustaining mountain glaciers. Ten major rivers to carry forward hitherto sustainable development of these peoples fall into question now. Further, in the wake of global climate change today, the delicate HKH ecosystem becomes increasingly fragile to unfold manifold consequences and thereby take its toll on the population. And the same might turn apocalyptic in its magnanimity of irreversibledamage. Like time-bomb, thus, climate ticks to get blown off. As it is getting already too delayed for timely resort to safeguards, if still not taken care of in time, lawmakers ought to find the aftermath too late to lament for. Besides being conscious for climate discipline across the world, collective efforts on the part of all regional states together are imperative to minimize the damage. Therefore, each one has put hands together to be saved from the doomsday that appears to stand ahead to accelerate a catastrophicend, in the given speed of global climate change. As the largest Himalayan state and its central positioning at the top of the HKH, Nepal has had potential to play a criticalrole to engage regional climate change regime and thereby spearhead climate diplomacy worldwide to play regional capital of the HKH ecosystem. As regional superpower, India has had potential to usurp leadership avatar to this end. With reasoningof his own, the author pleads for better jurisprudence to attain regional environmental integrity inter se- rather than regional environmental integration alone- to defendthe vulnerable HKH ecosystem since the same constitutes common concern of humankind and much more so for themselves. Hence, to quote from Shakespeare, “To be or not to be, that is the question” is reasonable here. While states are engaged in the spree to cause mutually agreed destruction, global climate change- with deadly aftermath- poses the last and final unifier for them to turn United Nations in rhetoric sense o f the term.

scholarly journals Selecting global climate models for regional climate change studies

2009 ◽  
Vol 106 (21) ◽  
pp. 8441-8446 ◽  
Author(s):  
D. W. Pierce ◽  
T. P. Barnett ◽  
B. D. Santer ◽  
P. J. Gleckler
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Global Climate ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Global Climate Models

scholarly journals EFFECT OF THE REGIONAL CLIMATE CHANGE ON RUNOFF FROM THE LAKE ONEGO WATERSHED

2015 ◽  
Vol 2 ◽  
pp. 25
Author(s):  
L. E. Nazarova
Keyword(s):  
Climate Change ◽  
Water Balance ◽  
Air Temperature ◽  
Global Climate ◽  
Regional Climate ◽  
Hydrological Regime ◽  
Regional Climate Change ◽  
Mean Annual Precipitation ◽  
General Tendency ◽  
Temperature And Precipitation

As a result of the statistical analysis of the meteorological and water balance data for Onego Lake watershed over the period 1950-2000, noticeable changes were detected. It was found that time series of annual air temperature, precipitation and evapotranspiration over 50-year period contains positive linear trends, but no change in total streamflow to the lake has so far followed. Potential changes in the regional climate and hydrological regime for the period 2000-2050 were estimated using the results of numerical modeling with the ECHAM4/OPYC3 model for two scenarios of the global climate change. The estimation of these data shows that a general tendency to increase of annual air temperature and precipitation will remain in the new climate Mean annual precipitation will increase about 30-50 mm, mean average annual air temperature for the next 50-years period will rise from 1.6 up to 2.7-3.0 °C. Our estimation shows that for both scenarios all water balance parameters, excluding river runoff, will increase.

scholarly journals A Simple Equation for Regional Climate Change and Associated Uncertainty

2008 ◽  
Vol 21 (7) ◽  
pp. 1589-1604 ◽  
Author(s):  
Filippo Giorgi
Keyword(s):  
Climate Change ◽  
Global Climate ◽  
Regional Climate ◽  
Regional Climate Change ◽  
First Century ◽  
Temperature And Precipitation ◽  
Regional Temperature ◽  
Global Temperature Change ◽  
Simple Equations ◽  
Precipitation Changes

Abstract Simple equations are developed to express regional climate changes for the twenty-first century and associated uncertainty in terms of the global temperature change (GTC) without a dependence on the underlying emission pathways. The equations are applied to regional temperature and precipitation changes over different regions of the world, and relevant parameters are calculated using the latest multimodel ensemble of global climate change simulations. Examples are also shown of how to use the equations to develop probability density functions (PDFs) of regional climate change based on PDFs of GTC. The main advantage of these equations is that they can be used to estimate regional changes from GTC obtained either from simple and intermediate complexity models or from target CO2 stabilization concentrations.

scholarly journals Impact analysis of climate change for an Alpine catchment using high resolution dynamic downscaling of ECHAM4 time slices

2004 ◽  
Vol 8 (6) ◽  
pp. 1031-1045 ◽  
Author(s):  
H. Kunstmann ◽  
K. Schneider ◽  
R. Forkel ◽  
R. Knoche
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Climate Model ◽  
Global Climate ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Climate Scenario ◽  
Dynamic Downscaling ◽  
Hydrological Simulation ◽  
Recent Climate

Abstract. Global climate change affects spatial and temporal patterns of precipitation and so has a major impact on surface and subsurface water balances. While global climate models are designed to describe climate change on global or continental scales, their resolution is too coarse for them to be suitable for describing regional climate change. Therefore, regional climate models are applied to downscale the coarse meteorological fields to a much higher spatial resolution to take account of regional climate phenomena. The changes of atmospheric state due to regional climate change must be translated into surface and sub-surface water fluxes so that the impact on water balances in specific catchments can be investigated. This can be achieved by the coupled regional climatic/hydrological simulations presented here. The non-hydrostatic regional climate model MCCM was used for dynamic downscaling for two time slices of a global climate model simulation with the GCM ECHAM4 (IPCC scenario IS92a, "business as usual") from 2.8° × 2.8° to 4 × 4 km2 resolution for the years 1991–1999 and 2031–2039. This allowed derivation of detailed maps showing changes in precipitation and temperature in a region of southern Germany and the central Alps. The performance of the downscaled ECHAM4 to reproduce the seasonality of precipitation in central Europe for the recent climate was investigated by comparison with dynamically downscaled ECMWF reanalyses in 20 × 20 km2 resolution. The downscaled ECHAM4 fields underestimate precipitation significantly in summer. The ratio of mean monthly downscaled ECHAM4 and ECMWF precipitation showed little variation, so it was used to adjust the course of precipitation for the ECHAM4/MCCM fields before it was applied in the hydrological model. The high resolution meteorological fields were aggregated to 8-hour time steps and applied to the distributed hydrological model WaSiM to simulate the water balance of the alpine catchment of the river Ammer (c. 700 km2) at 100 × 100 m2 resolution. To check the reliability of the coupled regional climatic/hydrological simulation results for the recent climate, they were compared with those of a station-based hydrological simulation for the period 1991–1999. This study shows the changes in the temperature and precipitation distributions in the catchment from the recent climate to the future climate scenario and how these will affect the frequency distribution of runoff. Keywords: coupled climate-hydrology simulations, dynamic downscaling, distributed hydrological modelling, ECHAM4 climate scenario, alpine hydrology

scholarly journals Early emergence in a butterfly causally linked to anthropogenic warming

2010 ◽  
Vol 6 (5) ◽  
pp. 674-677 ◽  
Author(s):  
Michael R. Kearney ◽  
Natalie J. Briscoe ◽  
David J. Karoly ◽  
Warren P. Porter ◽  
Melanie Norgate ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Regional Climate ◽  
Climate Change Impacts ◽  
Regional Climate Change ◽  
Future Climate Change ◽  
Climate Data ◽  
Regional Warming

There is strong correlative evidence that human-induced climate warming is contributing to changes in the timing of natural events. Firm attribution, however, requires cause-and-effect links between observed climate change and altered phenology, together with statistical confidence that observed regional climate change is anthropogenic. We provide evidence for phenological shifts in the butterfly Heteronympha merope in response to regional warming in the southeast Australian city of Melbourne. The mean emergence date for H. merope has shifted −1.5 days per decade over a 65-year period with a concurrent increase in local air temperatures of approximately 0.16°C per decade. We used a physiologically based model of climatic influences on development, together with statistical analyses of climate data and global climate model projections, to attribute the response of H. merope to anthropogenic warming. Such mechanistic analyses of phenological responses to climate improve our ability to forecast future climate change impacts on biodiversity.

scholarly journals Current regional climate change studies in Hungary : a review

1999 ◽  
Vol 54 (3) ◽  
pp. 138-146 ◽  
Author(s):  
I. Matyasovszky ◽  
T. Weidinger ◽  
J. Bartholy ◽  
Z. Barcza
Keyword(s):  
Climate Change ◽  
Greenhouse Gases ◽  
Global Climate Change ◽  
Global Climate ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Future Climate Change ◽  
Local Effects ◽  
Temperature And Precipitation ◽  
Empirical Downscaling

Abstract. After focusing on the changes in Hungarian temperature and preeipitation during this Century, possible hydrological, agricultural and ecological consequences of a future climate change are described. These results have been obtained using a modified version of empirical downscaling techniques, developed to analyse the local effects of global climate change in a twofold concentration of atmospheric greenhouse gases scenario. In addition, regional changes in temperature and precipitation were examined with the help of the more specific stochastic downscaling method. The climate of Hungary has become warmer and drier over the last Century. It is to be expected that an increasing concentration of atmospheric greenhouse gases will enhance the tendency towards aridification.

scholarly journals Incorrect Asian aerosols affecting the attribution and projection of regional climate change in CMIP6 models

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Zhili Wang ◽  
Lei Lin ◽  
Yangyang Xu ◽  
Huizheng Che ◽  
Xiaoye Zhang ◽  
...  
Keyword(s):  
Climate Change ◽  
Radiative Forcing ◽  
Impact Analysis ◽  
Climate Model ◽  
Regional Climate ◽  
Eastern China ◽  
Coupled Model ◽  
Regional Climate Change ◽  
Anthropogenic Aerosol ◽  
Wide Range

AbstractAnthropogenic aerosol (AA) forcing has been shown as a critical driver of climate change over Asia since the mid-20th century. Here we show that almost all Coupled Model Intercomparison Project Phase 6 (CMIP6) models fail to capture the observed dipole pattern of aerosol optical depth (AOD) trends over Asia during 2006–2014, last decade of CMIP6 historical simulation, due to an opposite trend over eastern China compared with observations. The incorrect AOD trend over China is attributed to problematic AA emissions adopted by CMIP6. There are obvious differences in simulated regional aerosol radiative forcing and temperature responses over Asia when using two different emissions inventories (one adopted by CMIP6; the other from Peking university, a more trustworthy inventory) to driving a global aerosol-climate model separately. We further show that some widely adopted CMIP6 pathways (after 2015) also significantly underestimate the more recent decline in AA emissions over China. These flaws may bring about errors to the CMIP6-based regional climate attribution over Asia for the last two decades and projection for the next few decades, previously anticipated to inform a wide range of impact analysis.

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